NEW YORK Most U.S. shares ended little changed to lower on Wednesday, erasing early gains on concerns about global growth and sliding commodity-related shares, while greater calm surrounding the European banking sector boosted that region's shares.

The benchmark U.S. S&P 500 .SPX stock index rose as much as 1.6 percent following Federal Reserve Chair Janet Yellen's prepared testimony to Congress. It changed course and ended mostly flat, while the Dow Jones industrial average ended down 100 points.

Yellen acknowledged that tightening financial conditions and uncertainty about China posed risks, but told Congress she does not expect the central bank to reverse its rate hike program.

European shares snapped a seven-day losing streak, bolstered by solid earnings and a recovery in Deutsche Bank (DBKGn.DE) from 30-year lows. The euro zone's banking index .SX7E ended up 6.9 percent. It still appeared headed for a seventh straight weekly decline, the longest losing streak since 1998.

"Nervous investors have been selling strength in the market," said Alan Gayle, senior investment strategist at RidgeWorth Investments in Atlanta, citing persistent worries about global growth.

MSCI's all-country world equity index, which tracks shares in 45 nations, was last down 0.35 points or 0.1 percent, at 358.08.

The Dow Jones industrial average .DJI ended down 99.64 points, or 0.62 percent, at 15,914.74. The S&P 500 .SPX closed down 0.35 points, or 0.02 percent, at 1,851.86. The Nasdaq Composite .IXIC rose 14.83 points, or 0.35 percent, to 4,283.59.

Europe's broad FTSEurofirst 300 index .FTEU3 ended up 1.78 percent, at 1,241.49. On Tuesday, the index fell 1.6 percent and hit its lowest since September 2013.

Brent crude prices settled up 52 cents, or 1.72 percent, at $30.84 a barrel. U.S. crude settled down 49 cents, or 1.75 percent, at $27.45 a barrel.

The dollar hit 113.100 yen, its lowest since Nov. 2014, as investors packed into the safe-haven Japanese currency despite Yellen's comments.

The "dovish undertones" of Yellen's testimony reinforced the view "that the Fed is probably not going to go through with a rate increase next month," said Kathy Lien, managing director of BK Asset Management in New York.

Treasury yields dipped after the U.S. Treasury sold $23 billion in 10-year notes to solid demand, showing investors have been unfazed by this year's drop in yields.